Dortmund rejected a bid from United for Lewandowski in August, with the Bundesliga champions currently valuing the former Lech Poznan player at £24.4 million.

But with Lewandowski rejecting Dortmund's attempts to extend his current contract, which expires in June 2014, Borussia chief executive Hans-Joachim Watzke has admitted that a decision will be made on his future at the end of the season.

"We will have to make decisions in this case at the end of the season." Watzke said. "We may decide on economical factors.

"Would it be best to cash in a big fee? Or would it be even better to keep Lewandowski to ensure we are more likely to qualify for the Champions League with him in our side, as this would guarantee us big income?

"It's a decision we will have to take and it's our decision. It's not something to be decided by others. As often as I am talking to Robert, I do not have the impression he wants to leave us."